Ethanamine compounds and methods of using the same

ABSTRACT

The present invention is directed to ethanamine compounds, pharmaceutical compositions comprising the same, and methods of treating depression by administering the ethanamine compound.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a Continuation Application of U.S. application Ser.No. 13/219,892, filed on Aug. 29, 2011, which is a ContinuationApplication of U.S. application Ser. No. 12/644,046, filed on Dec. 22,2009, now U.S. Pat. No. 8,013,165 which claims the benefit under 35U.S.C. §119(e) of Provisional Application 61/140,673 filed Dec. 24,2008.

FIELD OF THE INVENTION

Disclosed herein is at least one ethanamine derivative, at least onepharmaceutical composition comprising at least one ethanamine derivativedisclosed herein, and at least one method of using at least oneethanamine derivative disclosed herein for treating depression. Thecompounds may also have utility in the treatment of other diseases,including Parkinson's disease, pain states, such as neuropathic pain, aswell as epilepsy and neurotrauma.

BACKGROUND OF THE INVENTION

Depression is a common mental disorder that occurs in persons of allgenders, ages, and backgrounds, affecting about 121 million peopleworldwide. Symptoms of depression include, but are not limited to,depressed mood, loss of interest or pleasure, feelings of guilt or lowself-worth, disturbed sleep or appetite, low energy, and poorconcentration, or any combination thereof. These problems can becomechronic or recurrent and lead to substantial impairments in anindividual's ability to take care of his or her everydayresponsibilities.

Depression is the leading cause of disability as measured by Years Livedwith a Disability (YLDs) and the fourth leading contributor to theglobal burden of disease as measured by Disability Adjusted Life Years(DALYs; i.e., the sum of years of potential life lost due to prematuremortality and the years of productive life lost due to disability) in2000. By the year 2020, depression is projected to reach second place inthe ranking of DALYs calculated for all ages, in both men and women.Today, depression is already the second cause of DALYs in the agecategory 15-44 years for both sexes combined. Whereas there are clearlya number of currently available treatments for depression, a significantproportion of patients are either incompletely treated (many residualsymptoms remain) or do not respond to treatment at all. Thus, noveltreatments for depression are needed. The present invention providescompounds, compositions, methods of preparing the same, and methods oftreating depression. Such compounds would have additional utility inother disorders as well, including pain, Parkinson's disease, epilepsyand neurotrauma.

SUMMARY OF THE INVENTION

The present invention provides compounds

2-methyl-1-phenyl-2-(pyridin-2-yl)propan-1-amine or a pharmaceuticallyacceptable salt thereof.

(R)-2-methyl-1-phenyl-2-(pyridin-2-yl)propan-1-amine or apharmaceutically acceptable salt thereof.

(S)-2-methyl-1-phenyl-2-(pyridin-2-yl)propan-1-amine or apharmaceutically acceptable salt thereof.

DESCRIPTION OF EMBODIMENTS

The features and advantages of the invention may be more readilyunderstood by those of ordinary skill in the art upon reading thefollowing detailed description. An advantage of the present invention isthe prevention of stilbazole formation. Stilbazole is an undesirableby-product. The effects of stilbazole on humans is not yet fullyappreciated but a product without stilbazole would be preferrable.

It is to be appreciated that certain features of the invention that are,for clarity reasons, described in the context of separate embodiments,may also be combined to form a single embodiment. Conversely, variousfeatures of the invention that are, for brevity reasons, described inthe context of a single embodiment, may also be combined so as to formsub-combinations thereof.

Unless specifically stated otherwise herein, references made in thesingular may also include the plural. For example, “a” and “an” mayrefer to either one, or one or more.

Embodiments identified herein as exemplary are intended to beillustrative and not limiting.

Unless otherwise indicated, any heteroatom with unsatisfied valences isassumed to have hydrogen atoms sufficient to satisfy the valences.

The definitions set forth herein take precedence over definitions setforth in any patent, patent application, and/or patent applicationpublication incorporated herein by reference.

Definitions of terms used in describing the invention are set forthherein below. Unless otherwise indicated, the initial definitionprovided for a group or term applies each time such group or term isused individually. Throughout the specification, groups and substituentsthereof may be chosen by one skilled in the field to provide stablemoieties and compounds.

Unless specified otherwise herein, the nomenclature used hereingenerally follows the examples and rules stated in Nomenclature ofOrganic Chemistry, Sections A, B, C, D, E, F, and H, Pergamon Press,Oxford, 1979.

The term “about” means±5% of the value it modifies. For example, “about”100 means 95 to 105.

The term “halogen” refers to chlorine, bromine, fluorine, and iodine.

The term “pharmaceutically acceptable”, as employed herein, indicatesthe subject matter being identified as “pharmaceutically acceptable” issuitable and physiologically acceptable for administration to apatient/subject. For example, the term “pharmaceutically acceptablesalt(s)” denotes suitable and physiologically acceptable salt(s).

The phrase “a compound of formula I, enantiomers thereof,pharmaceutically acceptable salts thereof, or mixtures thereof” orsimilar such phrases, refers to the free base of formula I orenantiomers thereof, pharmaceutically acceptable salts of formula I orenantiomers thereof, and/or mixtures of at least one free base offormula I or enantiomers thereof and at least one pharmaceuticallyacceptable salt of formula I or enantiomers thereof. Formula I is of thestructure

The term “therapeutically effective amount” refers to that amount of acompound sufficient to modulate one or more of the symptoms of thecondition or disease being treated.

A selection of in vivo hydrolysable amide forming groups for hydroxyinclude alkanoyl, benzoyl, phenylacetyl and substituted benzoyl andphenylacetyl, alkoxycarbonyl (to give alkyl carbonate esters),dialkylcarbamoyl and N-(dialkylaminoethyl)-N-alkylcarbamoyl (to givecarbamates), dialkylaminoacetyl and carboxyacetyl. Examples ofsubstituents on benzoyl include morpholino and piperazino linked from aring nitrogen atom via a methylene group to the 3- or 4-position of thebenzoyl ring.

The present invention provides the compound2-methyl-1-phenyl-2-(pyridin-2-yl)propan-1-amine or a pharmaceuticallyacceptable salt thereof.

The present invention provides the compound(R)-2-methyl-1-phenyl-2-(pyridin-2-yl)propan-1-amine or apharmaceutically acceptable salt thereof.

The present invention provides the compound(S)-2-methyl-1-phenyl-2-(pyridin-2-yl)propan-1-amine or apharmaceutically acceptable salt thereof.

The present invention provides the compound2-methyl-1-phenyl-2-(pyridin-2-yl)propan-1-amine fumarate.

The present invention provides the compound(R)-2-methyl-1-phenyl-2-(pyridin-2-yl)propan-1-amine fumarate.

The present invention provides the compound(S)-2-methyl-1-phenyl-2-(pyridin-2-yl)propan-1-amine fumarate.

The present invention provides a method of treating depression in ahuman which comprises administering to a person in need thereof atherapeutic effective amount of a compound or a pharmaceuticallyacceptable salt thereof, where the compound is2-methyl-1-phenyl-2-(pyridin-2-yl)propan-1-amine.

The present invention provides a method of treating depression in ahuman which comprises administering to a person in need thereof atherapeutic effective amount of a compound or a pharmaceuticallyacceptable salt thereof, where the compound is(R)-2-methyl-1-phenyl-2-(pyridin-2-yl)propan-1-amine.

The present invention provides a method of treating depression in ahuman which comprises administering to a person in need thereof atherapeutic effective amount of a compound or a pharmaceuticallyacceptable salt thereof, where the compound is(S)-2-methyl-1-phenyl-2-(pyridin-2-yl)propan-1-amine.

The present invention provides a method of treating depression in ahuman which comprises administering to a person in need thereof atherapeutic effective amount of a compound or a pharmaceuticallyacceptable salt thereof, where the compound is2-methyl-1-phenyl-2-(pyridin-2-yl)propan-1-amine fumarate.

The present invention provides a method of treating depression in ahuman which comprises administering to a person in need thereof atherapeutic effective amount of a compound or a pharmaceuticallyacceptable salt thereof, where the compound is(R)-2-methyl-1-phenyl-2-(pyridin-2-yl)propan-1-amine fumarate.

The present invention provides a method of treating depression in ahuman which comprises administering to a person in need thereof atherapeutic effective amount of a compound or a pharmaceuticallyacceptable salt thereof, where the compound is(S)-2-methyl-1-phenyl-2-(pyridin-2-yl)propan-1-amine fumarate.

The present invention provides a method of treating major depressivedisorder in a human which comprises administering to a person in needthereof a therapeutic effective amount of a compound or apharmaceutically acceptable salt thereof, where the compound is2-methyl-1-phenyl-2-(pyridin-2-yl)propan-1-amine.

The present invention provides a method of treating major depressivedisorder in a human which comprises administering to a person in needthereof a therapeutic effective amount of a compound or apharmaceutically acceptable salt thereof, where the compound is(R)-2-methyl-1-phenyl-2-(pyridin-2-yl)propan-1-amine.

The present invention provides a method of treating major depressivedisorder in a human which comprises administering to a person in needthereof a therapeutic effective amount of a compound or apharmaceutically acceptable salt thereof, where the compound is(S)-2-methyl-1-phenyl-2-(pyridin-2-yl)propan-1-amine.

The present invention provides a method of treating major depressivedisorder in a human which comprises administering to a person in needthereof a therapeutic effective amount of a compound or apharmaceutically acceptable salt thereof, where the compound is2-methyl-1-phenyl-2-(pyridin-2-yl)propan-1-amine fumarate.

The present invention provides a method of treating major depressivedisorder in a human which comprises administering to a person in needthereof a therapeutic effective amount of a compound or apharmaceutically acceptable salt thereof, where the compound is(R)-2-methyl-1-phenyl-2-(pyridin-2-yl)propan-1-amine fumarate.

The present invention provides a method of treating major depressivedisorder in a human which comprises administering to a person in needthereof a therapeutic effective amount of a compound or apharmaceutically acceptable salt thereof, where the compound is(S)-2-methyl-1-phenyl-2-(pyridin-2-yl)propan-1-amine fumarate.

The present invention provides a pharmaceutical composition comprising2-methyl-1-phenyl-2-(pyridin-2-yl)propan-1-amine or a pharmaceuticallyacceptable salt thereof and a pharmaceutically acceptable adjuvant,carrier, or diluent.

The present invention provides a pharmaceutical composition comprising(R)-2-methyl-1-phenyl-2-(pyridin-2-yl)propan-1-amine or apharmaceutically acceptable salt thereof and a pharmaceuticallyacceptable adjuvant, carrier, or diluent.

The present invention provides a pharmaceutical composition comprising(S)-2-methyl-1-phenyl-2-(pyridin-2-yl)propan-1-amine or apharmaceutically acceptable salt thereof and a pharmaceuticallyacceptable adjuvant, carrier, or diluent.

The present invention provides a pharmaceutical composition comprising2-methyl-1-phenyl-2-(pyridin-2-yl)propan-1-amine fumarate or apharmaceutically acceptable salt thereof and a pharmaceuticallyacceptable adjuvant, carrier, or diluent.

The present invention provides a pharmaceutical composition comprising(R)-2-methyl-1-phenyl-2-(pyridin-2-yl)propan-1-amine fumarate or apharmaceutically acceptable salt thereof and a pharmaceuticallyacceptable adjuvant, carrier, or diluent.

The present invention provides a pharmaceutical composition comprising(S)-2-methyl-1-phenyl-2-(pyridin-2-yl)propan-1-amine fumarate or apharmaceutically acceptable salt thereof and a pharmaceuticallyacceptable adjuvant, carrier, or diluent.

The compounds of the present invention may be administered in the formof a prodrug which is broken down in the human or animal body to give acompound of the formula I. Examples of prodrugs include in vivohydrolysable amides of a compound of formula I. Various forms ofprodrugs are known in the art. For examples of such prodrug derivatives,see: a) Design of Prodrugs, edited by H. Bundgaard, (Elsevier, 1985) andMethods in Enzymology, Vol. 42, p. 309-396, edited by K. Widder, et al.(Academic Press, 1985); b) A Textbook of Drug Design and Development,edited by Krogsgaard-Larsen and H. Bundgaard, Chapter 5 “Design andApplication of Prodrugs”, by H. Bundgaard p. 113-191 (1991); c) H.Bundgaard, Advanced Drug Delivery Reviews, 8, 1-38 (1992); d) H.Bundgaard, et al., Journal of Pharmaceutical Sciences, 77, 285 (1988);and e) N. Kakeya, et al., Chem Pharm Bull, 32, 692 (1984).

It will be understood that when compounds of the present inventioncontain a chiral center, the compounds of the invention may exist in,and be isolated as, enantiomeric or as a racemic mixture. The presentinvention includes any possible enantiomers, racemates or mixturesthereof, of the compounds of formula I. The optically active forms ofthe compound of the invention may be prepared, for example, by chiralchromatographic separation of a racemate, by synthesis from opticallyactive starting materials or by asymmetric synthesis.

It will also be understood that certain compounds of the invention mayexist in solvated, for example hydrated, as well as unsolvated forms. Itwill further be understood the present invention encompasses all suchsolvated forms of the compounds of formula I.

The present invention includes compounds in the form of salts, inparticular acid addition salts. Suitable salts include all knownpharmaceutically acceptable salts including those formed with bothorganic and inorganic acids. Thus, suitable salts include those formedfrom hydrochloric, hydrobromic, sulfuric, phosphoric, citric, tartaric,lactic, pyruvic, acetic, succinic, fumaric, maleic, methanesulphonic,and benzenesulphonic acids. Without being held to any specific salt formit appears that fumaric salts are particularly suitable.

The present invention also provides methods of treating depressionincluding major depressive disorder in a human or other animalcomprising administering a therapeutically effective amount of any ofthe compounds, isomers, enantiomers thereof, or pharmaceuticallyacceptable salts of the compounds or pharmaceutically acceptable saltsof the isomers, enantiomers, described herein, or mixture of any of thecompounds, isomers, enantiomers thereof, or pharmaceutically acceptablesalts of the compounds or pharmaceutically acceptable salts of theisomers, enantiomers, described above. In some embodiments, the human orother animal will be in need thereof of such treatment.

In a further aspect, the invention provides methods of treatingneurodegenerative disorders, for example Alzheimer's disease,Parkinson's disease, Huntington's disease, stroke, cerebral ischemia,cerebral palsy, the effects of hypoglycemia, epilepsy, dementia, AIDSrelated dementia, Olivo-ponto-cerebellar atrophy, perinatal asphyxia,anoxia, neuronal damage associated with substance abuse (for examplenarcotics or cocaine), retinopathies, schizophrenia, ischemic statesafter cardiac arrest or surgical operations, amyotrophic lateralsclerosis (ALS), coronary bypass disease, or fibromyalgia.

In a further aspect, the invention provides a low affinity NMDAantagonist, in particular a compound of formula I, in the manufacture ofa medicament for use in the prevention or treatment of the abovedisorders, in particular for the prevention or treatment of depressionincluding major depressive disorder.

The present invention also provides uses of any of the compounds,enantiomers thereof, or pharmaceutically acceptable salts of thecompounds or enantiomers described above for treating depression in ahuman.

The present invention also provides compounds, enantiomers thereof, orpharmaceutically acceptable salts of the compounds or enantiomersdescribed above for treating depression in a human.

The present invention also provides compounds, enantiomers thereof, orpharmaceutically acceptable salts of the compounds or enantiomersdescribed above for use in the manufacture of a medicament for thetreatment of depression.

The compounds according to the present invention may be administered byany route, including orally, intramuscularly, subcutaneously, topically,intranasally, intraperitoneally, intrathoracically, intravenously,epidurally, intrathecally, intracerebroventricularly and by injectioninto the joints. In one embodiment of the invention, the route ofadministration may be orally, intravenously or intramuscularly.

For preparing pharmaceutical compositions from the compounds of thisinvention, inert, pharmaceutically acceptable carriers can be eithersolid or liquid. Solid form preparations include powders, tablets,dispersible granules, capsules, cachets, and suppositories.

A solid carrier can be one or more substances, which may also act asdiluents, flavoring agents, solubilizers, lubricants, suspending agents,binders, or tablet disintegrating agents; it can also be anencapsulating material. In powders, the carrier is a finely dividedsolid, which is in a mixture with the finely divided active component.In tablets, the active component is mixed with the carrier having thenecessary binding properties in suitable proportions and compacted inthe shape and size desired.

For preparing suppository compositions, a low-melting wax such as amixture of fatty acid glycerides and cocoa butter is first melted andthe active ingredient is dispersed therein by, for example, stirring.The molten homogeneous mixture is then poured into convenient sizedmoulds and allowed to cool and solidify.

Suitable carriers are magnesium carbonate, magnesium stearate, talc,lactose, sugar, pectin, dextrin, starch, tragacanth, methyl cellulose,sodium carboxymethyl cellulose, a low-melting wax, cocoa butter, and thelike.

Tablets, powders, cachets, and capsules can be used as solid dosageforms suitable for oral administration.

Liquid from compositions include solutions, suspensions, and emulsions.Sterile water or water-propylene glycol solutions of the activecompounds may be mentioned as an example of liquid preparations suitablefor parenteral administration. Liquid compositions can also beformulated in solution in aqueous polyethylene glycol solution.

Aqueous solutions for oral administration can be prepared by dissolvingthe active component in water and adding suitable colorants, flavoringagents, stabilizers, and thickening agents as desired. Aqueoussuspensions for oral use can be made by dispersing the finely dividedactive component in water together with a viscous material such asnatural synthetic gums, resins, methyl cellulose, sodium carboxymethylcellulose, and other suspending agents known to the pharmaceuticalformulation art.

The term “composition” is intended to include the formulation of theactive component with encapsulating material as a carrier providing acapsule in which the active component (with or without other carriers)is surrounded by a carrier which is thus in association with it.Similarly, cachets are included.

Prophylaxis is expected to be particularly relevant to the treatment ofpersons who have suffered a previous episode of, or are otherwiseconsidered to be at increased risk of, the disease or condition inquestion. Persons at risk of developing a particular disease orcondition generally include those having a family history of the diseaseor condition, or those who have been identified by genetic testing orscreening to be particularly susceptible to developing the disease orcondition.

In some embodiments, the pharmaceutical composition is in unit dosageform. In such form, the composition is divided into unit dosescontaining appropriate quantities of the active component. The unitdosage form can be a packaged preparation, the package containingdiscrete quantities of the preparations, for example, packeted tablets,capsules, and powders in vials or ampoules. The unit dosage form canalso be a capsule, cachet, or tablet itself, or it can be theappropriate number of any of these packaged forms.

The dosage will depend on the route of administration, the severity ofthe disease, age and weight of the patient and other factors normallyconsidered by the attending physician, when determining the individualregimen and dosage level at the most appropriate for a particularpatient.

Suitable daily dose ranges are from about 0.05 mg/kg to about 5.0 mg/kg.Unit doses may be administered conventionally once or more than once aday; for example, 2, 3, or 4 times a day; more usually 1 or 2 times aday. A typical dosing regimen would be oral, intramuscular orintravenous, once or twice a week to once or twice per day at 3.5 to 350mg.

The pharmaceutical composition comprising the compound of the inventionmay conveniently be formulated as tablets, pills, capsules, syrups,powders or granules for oral administration; sterile parental orsubcutaneous solutions, suspensions for parental administration; orsuppositories for rectal administration; all of which are well known inthe art.

For clinical use, the compounds of the invention are formulated intopharmaceutical formulations for oral, rectal, parenteral or any othermode of administration. The pharmaceutical formulation contains at leastone compound of the invention in combination with one or morepharmaceutically acceptable ingredients. The carrier may be in the formof a solid, semi-solid or liquid diluent, or a capsule. Thesepharmaceutical preparations are a further object of the invention.Depending on the mode of administration, the pharmaceutical compositioncan comprise from about 0.05% w to about 99% w (percent by weight), orfrom about 0.05% w to about 80% w, or from about 0.10% w to about 70% w,or from about 0.10% w to about 50% w, of active ingredient, allpercentages by weight being based on total composition.

In the preparation of pharmaceutical formulations containing at leastone compound of the present invention in the form of dosage units fororal administration the compound selected may be mixed with solid,powdered ingredients, or another suitable ingredient, as well as withdisintegrating agents and lubricating agents. The mixture is thenprocessed into granules or pressed into tablets.

Soft gelatin capsules may be prepared with capsules containing a mixtureof the active compound or compounds of the invention. Hard gelatincapsules may contain granules of the active compound. Hard gelatincapsules may also contain the active compound in combination with solidpowdered ingredients.

Dosage units for rectal administration may be prepared (i) in the formof suppositories which contain the active substance mixed with a neutralfat base; (ii) in the form of a gelatin rectal capsule which containsthe active substance in a mixture with suitable vehicles for gelatinrectal capsules; (iii) in the form of a ready-made micro enema; or (iv)in the form of a dry micro enema formulation to be reconstituted in asuitable solvent just prior to administration.

Liquid preparations for oral administration may be prepared in the formof syrups or suspensions, e.g., solutions or suspensions containing theactive ingredient. If desired, such liquid preparations may containcoloring agents, flavoring agents, saccharine and carboxymethylcellulose or other thickening agent. Liquid preparations for oraladministration may also be prepared in the form of a dry powder to bereconstituted with a suitable solvent prior to use.

Solutions for parenteral administration may be prepared as a solution ofat least one compound of the invention in a pharmaceutically acceptablesolvent. These solutions may also contain stabilizing ingredients and/orbuffering ingredients and are dispensed into unit doses in the form ofampoules or vials. Solutions for parenteral administration may also beprepared as a dry preparation to by reconstituted with a suitablesolvent extemporaneously before use.

Combinations wherein a compound of formula (I) or a pharmaceuticallyacceptable salt, solvate or in vivo hydrolysable amide thereof, or apharmaceutical composition or formulation comprising a compound offormula (I) is administered concurrently, simultaneously, sequentiallyor separately with another pharmaceutically active compound or compoundsselected from the following:

(i) antidepressants such as agomelatine, amitriptyline, amoxapine,bupropion, citalopram, clomipramine, desipramine, doxepin, duloxetine,elzasonan, escitalopram, fluvoxamine, fluoxetine, gepirone, imipramine,ipsapirone, maprotiline, nortriptyline, nefazodone, paroxetine,phenelzine, protriptyline, ramelteon, reboxetine, robalzotan,sertraline, sibutramine, thionisoxetine, tranylcypromaine, trazodone,trimipramine, venlafaxine and equivalents and pharmaceutically activeisomer(s) and metabolite(s) thereof.(ii) atypical antipsychotics including for example quetiapine, lithiumand equivalents thereof and pharmaceutically active isomer(s) andmetabolite(s) thereof.(iii) antipsychotics including for example amisulpride, aripiprazole,asenapine, benzisoxidil, bifeprunox, carbamazepine, clozapine,chlorpromazine, debenzapine, divalproex, duloxetine, eszopiclone,haloperidol, iloperidone, lamotrigine, loxapine, mesoridazine,olanzapine, paliperidone, perlapine, perphenazine, phenothiazine,phenylbutylpiperidine, pimozide, prochlorperazine, risperidone,sertindole, sulpiride, suproclone, suriclone, thioridazine,trifluoperazine, trimetozine, valproate, valproic acid, zopiclone,zotepine, ziprasidone and equivalents and pharmaceutically activeisomer(s) and metabolite(s) thereof.(iv) anxiolytics including for example alnespirone, azapirones,benzodiazepines, barbiturates such as adinazolam, alprazolam, balezepam,bentazepam, bromazepam, brotizolam, buspirone, clonazepam, clorazepate,chlordiazepoxide, cyprazepam, diazepam, diphenhydramine, estazolam,fenobam, flunitrazepam, flurazepam, fosazepam, lorazepam, lormetazepam,meprobamate, midazolam, nitrazepam, oxazepam, prazepam, quazepam,reclazepam, tracazolate, trepipam, temazepam, triazolam, uldazepam,zolazepam and equivalents and pharmaceutically active isomer(s) andmetabolite(s) thereof.(v) anticonvulsants including for example carbamazepine, valproate,lamotrogine, gabapentin and equivalents and pharmaceutically activeisomer(s) and metabolite(s) thereof.(vi) Alzheimer's therapies including for example donepezil, memantine,tacrine and equivalents and pharmaceutically active isomer(s) andmetabolite(s) thereof.(vii) Parkinson's therapies including for example deprenyl, L-dopa,Requip, Mirapex, MAOB inhibitors such as selegine and rasagiline, comPinhibitors such as Tasmar, A-2 inhibitors, dopamine reuptake inhibitors,NMDA antagonists, Nicotine agonists, Dopamine agonists and inhibitors ofneuronal nitric oxide synthase and equivalents and pharmaceuticallyactive isomer(s) and metabolite(s) thereof.(viii) migraine therapies including for example almotriptan, amantadine,bromocriptine, butalbital, cabergoline, dichloralphenazone, eletriptan,frovatriptan, lisuride, naratriptan, pergolide, pramipexole,rizatriptan, ropinirole, sumatriptan, zolmitriptan, zomitriptan, andequivalents and pharmaceutically active isomer(s) and metabolite(s)thereof.(ix) stroke therapies including for example abciximab, activase,NXY-059, citicoline, crobenetine, desmoteplase, repinotan, traxoprodiland equivalents and pharmaceutically active isomer(s) and metabolite(s)thereof.(x) over active bladder urinary incontinence therapies including forexample darafenacin, falvoxate, oxybutynin, propiverine, robalzotan,solifenacin, tolterodine and equivalents and pharmaceutically activeisomer(s) and metabolite(s) thereof.(xi) neuropathic pain therapies including for example gabapentin,lidoderm, pregablin and equivalents and pharmaceutically activeisomer(s) and metabolite(s) thereof.(xii) nociceptive pain therapies such as celecoxib, etoricoxib,lumiracoxib, rofecoxib, valdecoxib, diclofenac, loxoprofen, naproxen,paracetamol and equivalents and pharmaceutically active isomer(s) andmetabolite(s) thereof.(xiii) insomnia therapies including for example agomelatine,allobarbital, alonimid, amobarbital, benzoctamine, butabarbital,capuride, chloral, cloperidone, clorethate, dexclamol, ethchlorvynol,etomidate, glutethimide, halazepam, hydroxyzine, mecloqualone,melatonin, mephobarbital, methaqualone, midaflur, nisobamate,pentobarbital, phenobarbital, propofol, ramelteon, roletamide,triclofos, secobarbital, zaleplon, zolpidem and equivalents andpharmaceutically active isomer(s) and metabolite(s) thereof.(xiv) mood stabilizers including for example carbamazepine, divalproex,gabapentin, lamotrigine, lithium, olanzapine, quetiapine, valproate,valproic acid, verapamil, and equivalents and pharmaceutically activeisomer(s) and metabolite(s) thereof.(xv) analgesics including for example acetaminophen, ibuprofen,naproxen, hydrocodone, oxycodone, diclofenac, piroxicam, etodolac,fenoprofen, ketoprofen, ketorolac, loxoprofen, meclofenamate, meloxicam,gabapentin, paracetamol, morphine, fentyl, cyclooxygenase-2-inhibitors,celecoxib, etoricoxib, lumiracoxib, rofecoxib, valdecoxib, codeine,propoxyphene, tramadol and equivalents and pharmaceutically activeisomer(s) and metabolite(s) thereof.

Such combination products employ the compounds of this invention withinthe dosage range described herein and the other pharmaceutically activecompound or compounds within approved dosage

In general, compounds of the present invention can be prepared inaccordance with the following Schemes and the general knowledge of oneskilled in the art and/or in accordance with the methods set forth inthe Examples that follow. Solvents, temperatures, pressures, and otherreaction conditions may readily be selected by one of ordinary skill inthe art. Starting materials are commercially available or readilyprepared by one skilled in the art.

Step 1: A compound in accordance with formula II can be obtained bytreating 2-ethylpyridine with a suitable strong base, such as, butyllithium, in an appropriate solvent, such as THF followed by an aromaticaldehyde.

Step 2: A compound in accordance with formula III can be obtained bytreating a compound in accordance with formula II with an appropriateoxidizing agent, such as a Swern oxidation agent, in an appropriatesolvent, such as DCM.

Step 3: A compound in accordance with formula IV can be obtained bytreating a compound in accordance with formula III with an appropriatestrong base, such as sodium hydride, in an appropriate solvent, such asTHF, and an appropriate alkylating agent, such as methyl iodide.

Step 4: A compound in accordance with formula I can be obtained bytreating a compound in accordance with formula IV with an appropriateamine source, such as ammonia, in an appropriate solvent, such asmethanol, and an appropriate reducing agent, such as sodium borohydride.

A compound in accordance with formula I can be obtained by treating acompound in accordance with formula V as prepared according to Panunzio,M. and Zarantonelo, P. Org. Proc. Res. Dev. (1998) 2 49-59) with acompound in accordance with formula VI prepared according to Pasquinetet al, Tetrahedron 54 (1998) 8771-8782) in an appropriate solvent, suchas THF.

The present invention also provides methods of preparing compoundsdescribed above comprising:

a) treating 2-ethylpyridine with a suitable strong base in anappropriate solvent, followed by an aromatic aldehyde to produce acompound of formula II

wherein R corresponds to the optional substituent on Ar₂ in the compoundof claim 1;

b) treating the compound of formula II with an appropriate oxidizingagent in an appropriate solvent to produce a compound of formula III

c) treating the compound of formula III with an appropriate strong basein an appropriate solvent and an appropriate alkylating agent to producea compound of formula IV.

and

d) treating the compound of formula IV with an appropriate amine sourcein an appropriate solvent and an appropriate reducing agent to producethe compound described above.

In some embodiments, in a) the suitable strong base is butyl lithium andthe solvent is tetrahydrofuran (THF).

In some embodiments, in b) the oxidizing agent is a Swern oxidationagent and the solvent is DCM.

In some embodiments, in c) the strong base is sodium hydride, thesolvent is tetrahydrofuran (THF), and the alkylating agent is methyliodide.

In some embodiments, in d) the amine source is ammonia, the solvent ismethanol, and the reducing agent is sodium borohydride.

The present invention also provides methods of preparing compoundsdescribed above comprising treating a compound of formula V

wherein R corresponds to the optional substituent on Ar₂ in thecompounds described above, and wherein R₅ is methyl, with a compound offormula VI

wherein K is potassium, or the potassium counterion, in an appropriatesolvent to produce the compounds described above.

In some embodiments, the solvent is tetrahydrofuran (THF).

It will be appreciated that certain of the various ring substituents inthe compounds of the present invention may be introduced by standardaromatic substitution reactions or generated by conventional functionalgroup modifications either prior to or immediately following theprocesses mentioned above, and as such are included in the processaspect of the invention. Such reactions and modifications include, forexample, introduction of a substituent by means of an aromaticsubstitution reaction, reduction of substituents, alkylation ofsubstituents and oxidation of substituents. The reagents and reactionconditions for such procedures are well known in the chemical art.Particular examples of aromatic substitution reactions include theintroduction of a nitro group using concentrated nitric acid, theintroduction of an acyl group using, for example, an acyl halide andLewis acid (such as aluminium trichloride) under Friedel Craftsconditions; the introduction of an alkyl group using an alkyl halide andLewis acid (such as aluminium trichloride) under Friedel Craftsconditions; and the introduction of a halogeno group. Particularexamples of modifications include the reduction of a nitro group to anamino group by for example, catalytic hydrogenation with a nickelcatalyst or treatment with iron in the presence of hydrochloric acidwith heating; oxidation of alkylthio to alkylsulphinyl oralkylsulphonyl.

It will also be appreciated that in some of the reactions mentionedherein it may be necessary/desirable to protect any sensitive groups inthe compounds. The instances where protection is necessary or desirableand suitable methods for protection are known to those skilled in theart. Conventional protecting groups may be used in accordance withstandard practice (for illustration, see Green and Wuts, ProtectiveGroups in Organic Synthesis, 3rd ed., John Wiley and Sons, 1999). Thus,if reactants include groups such as amino, carboxy or hydroxy it may bedesirable to protect the group in some of the reactions mentionedherein.

A suitable protecting group for an amino or alkylamino group is, forexample, an acyl group, for example an alkanoyl group such as acetyl, analkoxycarbonyl group, for example a methoxycarbonyl, ethoxycarbonyl ort-butoxycarbonyl group, an arylmethoxycarbonyl group, for examplebenzyloxycarbonyl, or an aroyl group, for example benzoyl. Thedeprotection conditions for the above protecting groups necessarily varywith the choice of protecting group. Thus, for example, an acyl groupsuch as an alkanoyl or alkoxycarbonyl group or an aroyl group may beremoved for example, by hydrolysis with a suitable base such as analkali metal hydroxide, for example lithium or sodium hydroxide.Alternatively an acyl group such as a t-butoxycarbonyl group may beremoved, for example, by treatment with a suitable acid as hydrochloric,sulfuric or phosphoric acid or trifluoroacetic acid and anarylmethoxycarbonyl group such as a benzyloxycarbonyl group may beremoved, for example, by hydrogenation over a catalyst such as palladiumon carbon, or by treatment with a Lewis acid for example borontris(trifluoroacetate). A suitable alternative protecting group for aprimary amino group is, for example, a phthaloyl group, which may beremoved by treatment with an alkylamine, for exampledimethylaminopropylamine, or with hydrazine.

A suitable protecting group for a hydroxy group is, for example, an acylgroup, for example an alkanoyl group such as acetyl, an aroyl group, forexample benzoyl, or an arylmethyl group, for example benzyl. Thedeprotection conditions for the above protecting groups will necessarilyvary with the choice of protecting group. Thus, for example, an acylgroup such as an alkanoyl or an aroyl group may be removed, for example,by hydrolysis with a suitable base such as an alkali metal hydroxide,for example lithium or sodium hydroxide. Alternatively an arylmethylgroup such as a benzyl group may be removed, for example, byhydrogenation over a catalyst such as palladium on carbon.

A suitable protecting group for a carboxy group is, for example, anesterifying group, for example a methyl or an ethyl group which may beremoved, for example, by hydrolysis with a base such as sodiumhydroxide, or for example a t-butyl group which may be removed, forexample, by treatment with an acid, for example an organic acid such astrifluoroacetic acid, or for example a benzyl group which may beremoved, for example, by hydrogenation over a catalyst such as palladiumon carbon.

The protecting groups may be removed at any convenient stage in thesynthesis using conventional techniques well known in the chemical art.

EXAMPLES

The invention is further defined in the following Examples. It should beunderstood that the Examples are given by way of illustration only. Fromthe above discussion and the Examples, one skilled in the art canascertain the essential characteristics of the invention, and withoutdeparting from the spirit and scope thereof, can make various changesand modifications to adapt the invention to various uses and conditions.As a result, the invention is not limited by the illustrative examplesset forth hereinbelow, but rather defined by the claims appended hereto.

All temperatures are in degrees Celsius (° C.). Unless otherwise stated,operations are carried out at room or ambient temperature (18-25° C.).

Unless otherwise noted, commercial reagents used in preparing theexample compounds are used as received without additional purification.

Unless otherwise noted, the solvents used in preparing the examplecompounds are commercial anhydrous grades and are used without furtherdrying or purification.

Unless otherwise noted, the following method is used to determinenuclear magnetic resonance spectrometry: a Varian Unity Inova 400spectrometer operating at 400 MHz for ¹H equipped with a 5 mm inversedetection triple resonance probe for detection of ¹H, ¹³C, ³¹P with themagnetic field provided by a 9.4 Tesla Oxford instrumentssuper-conducting magnet and a Sun Microsystems SunBlade 1000 workstationas host. Chemical shifts are reported in parts-per-million (δ) from atetramethylsilane internal standard.

Unless otherwise indicated, the following method is used for massspectrometer detection: a Waters ZMD quadrupole mass spectrometer linkedto a Waters 1525 LC system with Waters 996 diode array detector. Sampleinjection is done by a Waters 2700 autosampler. The spectrometer has anelectrospray source operating in positive and negative ion mode.Additional detection is achieved using a Sedex 65 ELS detector. All m/zratios are reported as the M+1 ion.

Chiral chromatography to separate enantiomers is performed using aBerger multi gram II supercritical fluid chromatography (SFC) systemequipped with an ADH column, 21.2×250 mm in size, running an isocraticgradient of 15% isopropanol with 0.5% isopropylamine in CO₂, a flow rateof 70 mL/minute and UV detection at 230 nm.

The names of the compounds exemplified herein are generated usingAutoNom 2000 within ISIS/Draw. AutoNom (Automatic Nomenclature) is achemical-name-generating program that assigns systematic IUPAC(International Union of Pure and Applied Chemistry) chemical names todrawn structures at the press of a button.

The following abbreviations are employed herein: ACN: Acetonitrile;AcOH: acetic acid; CDCl₃; deuterated chloroform; D₃OD: deuteratedmethanol; DCM: dichloromethane; DMF: N,N-dimethylformamide; DMSO:dimethyl sulfoxide; DMSO-d6: deuterated dimethyl sulfoxide; ELS:evaporative light scattering; EtOAc: ethyl acetate; equiv: equivalent;Ex.: Example; HPLC: high performance liquid chromatography; HCl:hydrochloric acid; H₂O: water; H₂SO₄: sulfuric acid; LAH: Lithiumaluminum hydride; LCMS: liquid chromatography mass spectral detection;m/z: mass to charge ratio; LDA: lithium diisopropyl amide; MeOH:methanol; MgSO₄: magnesium sulfate; min.: minutes; MS: mass spectrum;M.p.: melting point; NaBH₄: sodium borohydride; n-BuLi:Lithium-1-butanide; NaHCO₃: sodium bicarbonate; NaOH: sodium hydroxide;Na₂SO₄: sodium sulfate; NH₄Cl: ammonium chloride; NMR: nuclear magneticresonance; N2: nitrogen gas: room temperature; rt=retention time; sat.:saturated; THF: tetrahydrofuran; and UV: Ultraviolet.

Example 1A 2-methyl-1-phenyl-2-(pyridin-2-yl)propan-1-amine via Scheme I

1-Phenyl-2-(pyridin-2-yl)propan-1-ol (2): n-Butyllithium (2.5 M, 15.0mL, 36.0 mmol) is added drop wise to a solution of 2-ethylpyridine (4.1mL, 36.0 mmol) in THF (56 mL) at −40° C. The resulting dark red solutionis kept at −30° C. to −20° C. for 1 hour and then cooled to −60° C. Asolution of benzaldehyde (3.7 mL, 36.0 mmol) in THF (10 mL) is addeddrop wise. The reaction mixture is allowed to warm up to 0° C. for 1hour and then quenched with aqueous NH₄Cl solution. The mixture isseparated and the aqueous phase is extracted with ethyl acetate (2×50mL). The extracts are combined, dried, concentrated and purified bycolumn chromatography (hexane/ethyl acetate 10:1 to 1:1) to give 2 (7.0g, 91%) as a yellow oil. This mixture contained two diastereoisomers(3:1). ¹H NMR (300 MHz, CDCl₃) for the major isomer: δ 1.14 (d, J=7.2Hz, 3H), 2.98 (q, J=6.9 Hz, 1H), 4.70-4.75 (m, 1H), 5.13-5.16 (m, 1H),6.80-7.39 (m, 8H), 8.34 (d, J=4.8 Hz, 1H).

1-Phenyl-2-(pyridin-2-yl)propan-1-one (3): A solution of DMSO (5.5 mL,77.5 mmol) in dichloromethane (10 mL) is added drop wise to a solutionof oxalyl chloride (3.3 mL, 39.0 mmol) in dichloromethane (100 mL) withthe internal temperature under −60° C. The reaction mixture is stirredfor 15 minutes and then a solution of1-phenyl-2-(pyridin-2-yl)propan-1-ol (2) (7.0 g, 32.8 mmol) indichloromethane (10 mL) is added slowly to keep the internal temperatureunder −60° C. After 30 minutes, triethylamine (22.3 mL, 0.16 mol) isadded slowly at −78° C. After 15 minutes, the reaction is allowed towarm up to 0° C. for 30 minutes and then quenched with water. Themixture is separated and the aqueous phase is extracted withdichloromethane (2×50 mL). The extracts are combined, washed with brine,dried, concentrated and purified by column chromatography (hexane/ethylacetate 10:1 to 4:1) to give 3 (6.4 g, 91%) as a yellow oil. ¹H NMR (300MHz, CDCl₃): δ 1.51-1.54 (m, 3H), 4.84-4.92 (m, 1H), 7.03-708 (m, 1H),7.18-7.20 (m, 2H), 7.30-7.35 (m, 1H), 7.40-7.43 (m, 1H), 7.52-7.57 (m,1H), 7.95-7.98 (m, 2H), 8.47-8.48 (m, 1H).

2-Methyl-1-phenyl-2-(pyridin-2-yl)propan-1-one (4): A solution ofcompound 3 (3.0 g, 14.2 mmol) in THF (10 mL) is added to a suspension ofsodium hydride (60%, 0.63 g, 15.6 mmol) in THF (60 mL) at 0° C. Thereaction mixture is kept at the same temperature for 2 hours and methyliodide (0.93 mL, 14.9 mmol) is added at 0° C. The reaction mixture isallowed to warm up to room temperature overnight and then quenched withwater. The mixture is separated and the aqueous phase is extracted withethyl acetate (2×40 mL). The extracts are combined, washed with brine,dried, concentrated and purified by column chromatography (hexane/ethylacetate 50:1 to 4:1) to give 4 (2.2 g, 69%) as a yellow solid.

2-Methyl-1-phenyl-2-(pyridin-2-yl)propan-1-amine dihydrochloride (1):Freshly distilled Ti(O-iPr)₄ (11.2 mL, 38.0 mmol) is added to a solutionof 4 (4.4 g, 19.0 mmol) in ammonia in methanol (7 M, 30 mL). Thereaction mixture is stirred at room temperature for 12 hours and thencooled to 0° C. NaBH₄ (1.4 g, 38.0 mmol) is added slowly. The reactionis then warmed up to room temperature for 3 hours and then poured intoammonium hydroxide (50 mL). The mixture is extracted with ethyl acetate(2×50 mL). The extracts are combined, washed with brine, dried,concentrated and purified by column chromatography (pretreated withtriethylamine) (DCM/methanol 20:1) to yield the free base of 1 (3.0 g)as a yellow oil. This oil is dissolved in isopropyl acetate (50 mL) anda solution of 5-6 N HCl in isopropyl alcohol (4.0 mL) is added. Themixture is concentrated, dissolved in methanol, concentrated andtriturated in ether to yield 1 (4.0 g, 60%) as a white solid. M.p.=188°C. ¹H NMR (300 MHz, CD₃OD): δ 1.59 (s, 3H), 1.76 (s, 3H), 5.09 (s, 1H),7.25-7.28 (m, 2H), 7.38-7.40 (m, 3H), 8.00 (t, J=6.6 Hz, 1H), 8.11 (d,J=6.9 Hz, 1H), 8.56 (t, J=7.8 Hz, 1H), 8.77 (d, J=5.7 Hz, 1H); ¹³C NMR(75 MHz, CD₃OD): δ 22.2, 22.6, 43.7, 62.4, 126.2, 126.4, 128.1, 128.9,129.6, 133.3, 142.9, 146.9. MS: m/z 227.

Example 1B 2-methyl-1-phenyl-2-(pyridin-2-yl)propan-1-amine via SchemeII

2-Methyl-1-phenyl-2-(pyridin-2-yl)propan-1-amine dihydrochloride. To astirred solution of benzaldehyde (3.44 mL, 33.92 mmol) in THF (35 mL) isadded a THF solution of lithium bis(trimethylsilyl)amide (37.3 mL, 37.32mmol) at 0° C. The mixture is stirred at 0° C. for 2 hours. To theresulting solution is added (2-(pyridin-2-yl)propan-2-yl)potassium (6.48g, 40.71 mmol) at −20 to −15° C. drop wise prepared in the followingmanner: in a dried, nitrogen-flushed flask was placed potassium2-methylpropan-2-olate (61.9 mL, 61.89 mmol) (1.0 M in THF) anddiisopropylamine (8.75 mL, 61.89 mmol). The mixture is cooled to −20° C.and BuLi (30.9 mL, 49.51 mmol) is slowly added to give a yellowsolution. The reaction mixture is then cooled to −50° C. and2-isopropylpyridine (5 g, 41.26 mmol) is added and the mixture stirred30 minutes. The mixture is then stirred at −20° C. for 30 minutes, andsat. NH₄Cl is added. The mixture is extracted with EA (3×). Combined EAare washed with sat. NaCl, dried over Na₂SO₄, filtered and concentratedby ISCO column (240 g), eluting with 0-70% EA/Hex, then 5% MeOH/DCM togive 2-methyl-1-phenyl-2-(pyridin-2-yl)propan-1-amine (6.07 g, 79%) asan yellow oil. This oil is dissolved in isopropyl acetate (50 mL) and asolution of 5-6 N HCl in isopropyl alcohol (4.0 mL) is added. Themixture is concentrated, dissolved in methanol, concentrated andtriturated in ether to yield 1 (4.0 g, 60%) as a white solid. M.p.=188°C. ¹H NMR (300 MHz, CD₃OD): δ 1.59 (s, 3H), 1.76 (s, 3H), 5.09 (s, 1H),7.25-7.28 (m, 2H), 7.38-7.40 (m, 3H), 8.00 (t, J=6.6 Hz, 1H), 8.11 (d,J=6.9 Hz, 1H), 8.56 (t, J=7.8 Hz, 1H), 8.77 (d, J=5.7 Hz, 1H); ¹³C NMR(75 MHz, CD₃OD): δ 22.2, 22.6, 43.7, 62.4, 126.2, 126.4, 128.1, 128.9,129.6, 133.3, 142.9, 146.9. MS: m/z 227.

Example 2

(S)-2-methyl-1-phenyl-2-(pyridin-2-yl)propan-1-amine is preparedstarting from racemic 2-methyl-1-phenyl-2-(pyridin-2-yl)propan-1-amineusing chiral SFC chromatography. This oil is dissolved in isopropylacetate and a solution of 5-6 N HCl in isopropyl alcohol is added. Themixture is concentrated, and triturated in ether to yield the titlecompound as a white solid. M.p.=188° C. ¹HNMR (300 MHz, CD₃OD): δ 1.59(s, 3H), 1.76 (s, 3H), 5.09 (s, 1H), 7.25-7.28 (m, 2H), 7.38-7.40 (m,3H), 8.00 (t, J=6.6 Hz, 1H), 8.11 (d, J=6.9 Hz, 1H), 8.56 (t, J=7.8 Hz,1H), 8.77 (d, J=5.7 Hz, 1H). MS: m/z 227.

An alternative route to generate Example 2 is described below

(a) 2-Isopropylpyridine

2-Isopropylpyridine was prepared by the method of P. Rocca, et. al.(Tetrahedron Vol. 54, pp. 8771-8782 (1998). A solution of2-ethylpyridine (1000 g, 9.332 moles) in anhydrous Tetrahydrofuran (6000mL) was cooled to −35° C. by a dry ice/acetone bath. n-Butyllithium(3970 mL of 2.5 Molar, 9.925 moles) was added at a fast drop wise rateover a period of 1.5 hours, while maintaining the internal temperatureat −20° C. to −25° C. Stirring was continued for an additional 1.5 hoursat −20° C., then the reaction was cooled to −45° C. Iodomethane (642 mL,1458 g, 10.272 moles) was added at a moderate drop wise rate over aperiod of 1.5 hours, while maintaining the reaction temperature between−40° C. and −45° C. After the addition was complete, the mixture wasallowed to stir for an additional 2 hours at −40° C., then was quenchedby the fast drop wise addition of water (4000 mL) added over a period of30 minutes. The reaction mixture was cooled to 0° C. and treated withconcentrated Hydrochloric acid (1150 mL) added over a period of 15minutes. The mixture was allowed to stir for an additional hour whilewarming to 15° C., then was transferred to a separatory funnel withdiethyl ether (2000 mL), and the layers separated. The aqueous phase wasfurther washed with diethyl ether (3×1000 mL), then made basic (pH=9) bytreatment with solid potassium carbonate. The aqueous mixture wasextracted with diethyl ether (4×1000 mL). The combined extracts werewashed with saturated brine (1000 mL) then dried (anhydrous magnesiumsulfate). Filtration, followed by removal of the solvent under reducedpressure at room temperature, gave the crude product as a reddish-orangeliquid (˜2000 mL). This crude product was distilled (twice) atatmospheric pressure through a three inch, glass vigreaux column,collecting the desired 2-isopropylpyridine (b.p. 158-163° C.) as a lightyellow liquid (926 g, 82% yield). ¹H NMR (300 MHz, CHLOROFORM-d) δ ppm8.53 (d, J=4.22 Hz, 1H) 7.59 (td, J=7.59, 1.69 Hz, 1H) 7.16 (d, J=8.01Hz, 1H) 7.08 (ddd, J=7.38, 4.85, 0.84 Hz, 1H) 2.94-3.25 (m, J=6.91,6.91, 6.91, 6.91, 6.91, 6.74 Hz, 1H) 1.31 (d, J=6.74 Hz, 6H).

(b) (R,E)-N-benzylidene-2-methylpropane-2-sulfinamide

To a solution of (R)-2-methylpropane-2-sulfinamide (1032 g, 8.515 moles)in dichloromethane (14000 mL) was added benzaldehyde (1000 g, 9.423moles) in one portion at room temperature. Anhydrous copper (II) sulfate(2718 g, 17.029 moles) was added in portions as a solid over a 10-minuteperiod, and washed down with additional dichloromethane (1000 mL). Thereaction mixture was allowed to stir for 45 hours at room temperature,and was checked for completion by HPLC. The mixture was filtered througha pad of Celite to remove the copper (II) sulfate. The filter cake waswashed with dichloromethane (4×1500 mL), and the combined filtratesconcentrated under reduced pressure to a cloudy yellow oil (1914 g, 107%of theory). The crude product was subjected to chromatography oversilica gel, eluting with a gradient of 0-10% ethyl acetate indichloromethane to yield the purified sulfinamide as a pale yellow oil(1563 g, 88% yield). 1H NMR (300 MHz, CHLOROFORM-d) δ □ppm 8.60 (s, 1H)7.85 (dd, J=7.80, 1.48 Hz, 2H) 7.40-7.62 (m, 3H) 1.27 (s, 9H). MS: m/z210.

(c)(R)-2-methyl-N—((S)-2-methyl-1-phenyl-2-(pyridine-2-yl)propyl)propane-2-sulfinamide

To a 1.0 Molar solution of potassium t-butoxide in tetrahydrofuran (3000mL, 3.000 moles) was added diisopropylamine (425 mL, 306.8 g, 3.032moles). The resulting solution was cooled by a dry ice/acetone bath to−50° C. n-Butyllithium solution (980 mL of 2.5 Molar, 2.450 moles) wasadded drop wise over a period of 40 minutes, giving a bright orangesolution. The mixture was allowed to stir for an additional 20 minutesat −25° C., then was cooled back down to −55° C. 2-isopropylpyridine(240.0 g, 1.981 moles) was then added drop wise over a period of 20minutes while maintaining the internal temperature between −50° C. to−55° C., giving a deep, reddish-purple solution. The mixture was allowedto stir for an additional 2 hours at −50° C., then was used directly inthe next step.

To the cooled (−50° C.) mixture containing the 2-Isopropylpyridyl anionwas added a solution of(R,E)-N-benzylidene-2-methylpropane-2-sulfinamide (360.0 g, 1.720 moles)in anhydrous tetrahydrofuran (3000 mL), drop wise over a period of 3hours while maintaining the internal temperature between −50° C. and−55° C. The reaction mixture was allowed to warm gradually over 3 hoursto 0° C., then checked for completion by working up an aliquot andchecking by HPLC. The reaction was quenched by treatment with saturatedsodium bicarbonate solution (3000 mL), added drop wise over 20 minutes.After stirring for an additional 30 minutes, the mixture was furtherdiluted with water (3000 mL), and divided into three portions (˜4500 mLeach). Each portion was partitioned with ethyl acetate (1000 mL), andthe layers separated. The combined aqueous layer was further extractedwith ethyl acetate (3×1000 mL). The combined organic extracts werewashed with saturated brine (1500 mL), then dried (anhydrous magnesiumsulfate). Filtration, followed by removal of the solvent under reducedpressure, left the crude product as a cream-colored solid (575.8 g,101.3% crude yield), which was a 9:1 mixture of diastereomers. The crudematerial was recrystallized from a mixture of Hexane/EtOAc (2:1) to givepure desired single diastereomer (371.9 g, 65.4% yield). 1H NMR (300MHz, CHLOROFORM-d) δ ppm 8.62 (dd, J=4.85, 1.05 Hz, 1H) 7.52 (td,J=7.80, 2.11 Hz, 1H) 7.09-7.19 (m, 4H) 6.99 (d, J=8.01 Hz, 1H) 6.85-6.94(m, 2H) 5.80 (d, J=8.01 Hz, 1H) 4.49 (d, J=8.43 Hz, 1H) 1.46 (s, 3H)1.33 (s, 3H) 1.10 (s, 9H). MS: m/z 331.

(d) (S)-2-methyl-1-phenyl-2-(pyridine-2-yl)propan-1-amine

To a solution of(R)-2-methyl-N—((S)-2-methyl-1-phenyl-2-(pyridin-2-yl)propyl)propane-2-sulfinamide(1200 g, 3.631 moles) dissolved in dichloromethane (12000 mL) was added4N hydrogen chloride/dioxane solution (3000 mL, 12.00 moles) in a steadystream over a period of 1 hour at room temperature. A thick suspensionformed, which was continued stirring for 1.5 hours at 32° C.; at whichpoint Methanol (1000 mL) was added to improve stirring. After 30 minutesadditional stirring, all of the solids dissolved, giving a clear ambersolution and indicating complete reaction. The solvents were removedunder reduced pressure leaving a gummy amber residue. The residue wastaken up in distilled water (5000 mL), and the resulting solution washedwith diethyl ether (2×1000 mL) to remove neutral impurities. The acidicsolution was treated with solid Sodium hydroxide (400 g, 10.00 moles)until strongly basic (pH=11). The resulting aqueous mixture wasextracted with dichloromethane (2×1000 mL, then 2×500 mL). The combinedorganic extracts were dried (anhydrous magnesium sulfate). Filtration,followed by removal of the solvent under reduced pressure, left a thickamber syrup. This residue was further dried under high vacuum to yieldthe crude de-protected amine (880.9 g, 107.2% of theory). 1H NMR (300MHz, CHLOROFORM-d) δ ppm 8.64 (d, J=3.79 Hz, 1H) 7.57 (td, J=7.69, 1.90Hz, 1H) 7.05-7.30 (m, 7H) 4.48 (s, 1H) 1.47 (br.s., 2H) 1.36 (s, 3H)1.25 (s, 3H). MS: m/z 227.

(e) (S)-2-methyl-1-phenyl-2-(pyridine-2-yl)propan-1-amine Fumarate Salt

(S)-2-methyl-1-phenyl-2-(pyridine-2-yl)propan-1-amine (821.7 g, 3.63moles) was dissolved in methanol (5000 mL) giving a reddish-orangesolution. The solution was treated with Norit decolorizing Carbon (50 g)and stirred at gentle reflux for 2 hours. The hot solution was filteredthrough a pad of Celite, giving a light yellow filtrate. The Carbonfilter cake was further washed with hot methanol (2×1000 mL), and thewashes combined with the original filtrate. The decolorized solution wastreated with fumaric acid (421.4 g, 3.63 moles), added as a dry solidover a period of 5 minutes. The solution was allowed to stir at roomtemperature for 30 minutes, then was concentrated under reduced pressureto remove most of the methanol (6000 mL removed). The resulting thickamber syrup was diluted gradually with vigorous stirring with diethylether (7000 mL) until crystallization ensued. The mixture was stirredvigorously until a very healthy crop of crystals had formed. The mixturewas then further diluted with additional diethyl ether (2000 mL, totalvolume of 9000 mL) with vigorous stirring to complete thecrystallization. The crystals were collected by suction filtration andpulled free of liquors. The crystals were re-suspended in a mixture of9:1 diethyl ether/methanol (2000 mL) and stirred vigorously for severalminutes, then re-filtered and pulled dry. The process was repeated asecond time. The white crystals obtained from this treatment were driedto constant weight in the vacuum oven at 60° C. to yield(S)-2-methyl-1-phenyl-2-(pyridine-2-yl)propan-1-amine fumarate salt(1179.3 g, 95% yield). 1H NMR (300 MHz, DMSO-d 6) δ ppm 9.19 (br. s.,3H) 8.62 (d, J=3.37 Hz, 1H) 7.71 (td, J=7.80, 1.69 Hz, 1H) 7.17-7.39 (m,5H) 6.94-7.17 (m, 2H) 6.51 (s, 2H) 4.64 (s, 1H) 1.35 (s, 3H) 1.26 (s,3H). ¹³C NMR (75 MHz, DMSO-d 6): δ ppm 23.7, 25.7, 43.8, 62.7, 121.3,122.3, 128.0, 128.1, 128.6, 135.5, 137.4, 137.8, 148.7, 164.9, 168.3.MS: m/z 227.

Example 3

(R)-2-methyl-1-phenyl-2-(pyridin-2-yl)propan-1-amine is preparedstarting from racemic 2-methyl-1-phenyl-2-(pyridin-2-yl)propan-1-amineusing chiral SFC chromatography. This oil is dissolved in isopropylacetate and a solution of 5-6 N HCl in isopropyl alcohol is added. Themixture is concentrated, and triturated in ether to yield the titlecompound as a white solid. M.p.=188° C. ¹HNMR (300 MHz, CD₃OD): δ 1.59(s, 3H), 1.76 (s, 3H), 5.09 (s, 1H), 7.25-7.28 (m, 2H), 7.38-7.40 (m,3H), 8.00 (t, J=6.6 Hz, 1H), 8.11 (d, J=6.9 Hz, 1H), 8.56 (t, J=7.8 Hz,1H), 8.77 (d, J=5.7 Hz, 1H). MS: m/z 227.

Biological Evaluation

NMDA receptor antagonist activity can be measured in vitro by assaying acompound's ability to inhibit binding of the receptor antagonist10,11-dihdro-5-methyl-5H-dibenzo[a,d]-cyclohepten-5,10-imine (MK801) tothe receptor. The method is described by Foster and Wong, Br. J.Pharmacol. 91, 403-409 (1987).

The IC₅₀ values of examples 1-6 are set forth in Table 1.

TABLE 1 Compound of MK801 Binding Example # IC₅₀ (uM) Example 1 12Example 2 6.4 Example 3 35

What is claimed is:
 1. 2-Methyl-1-phenyl-2-(pyridin-2-yl)propan-1-amineor a pharmaceutically acceptable salt thereof.
 2. A compound as claimedin claim 1 which is 2-methyl-1-phenyl-2-(pyridin-2-yl)propan-1-amine ora hydrochloric, hydrobromic, sulfuric, phosphoric, citric, tartaric,lactic, pyruvic, acetic, succinic, fumaric, maleic, methanesulphonic orbenzenesulphonic acid salt thereof.
 3. A compound as claimed in claim 1which is 2-methyl-1-phenyl-2-(pyridin-2-yl)propan-1-amine fumarate.
 4. Acompound as claimed in claim 1 which is2-methyl-1-phenyl-2-(pyridin-2-yl)propan-1-amine.
 5. A compound asclaimed in claim 1 which is(S)-2-methyl-1-phenyl-2-(pyridin-2-yl)propan-1-amine or apharmaceutically acceptable salt thereof.
 6. A compound as claimed inclaim 1 which is (S)-2-methyl-1-phenyl-2-(pyridin-2-yl)propan-1-amine ora hydrochloric, hydrobromic, sulfuric, phosphoric, citric, tartaric,lactic, pyruvic, acetic, succinic, fumaric, maleic, methanesulphonic orbenzenesulphonic acid salt thereof.
 7. A compound as claimed in claim 1which is (S)-2-methyl-1-phenyl-2-(pyridin-2-yl)propan-1-amine fumarate.8. A compound as claimed in claim 1 which is(S)-2-methyl-1-phenyl-2-(pyridin-2-yl)propan-1-amine.
 9. Apharmaceutical composition comprising2-methyl-1-phenyl-2-(pyridin-2-yl)propan-1-amine or a pharmaceuticallyacceptable salt thereof and a pharmaceutically acceptable adjuvant,carrier, or diluent.
 10. A pharmaceutical composition as claimed inclaim 9 comprising (S)-2-methyl-1-phenyl-2-(pyridin-2-yl)propan-1-amineor a pharmaceutically acceptable salt thereof and a pharmaceuticallyacceptable adjuvant, carrier, or diluent.
 11. A pharmaceuticalcomposition as claimed in claim 9 comprising2-methyl-1-phenyl-2-(pyridin-2-yl)propan-1-amine fumarate or apharmaceutically acceptable salt thereof and a pharmaceuticallyacceptable adjuvant, carrier, or diluent.
 12. A pharmaceuticalcomposition as claimed in claim 9 comprising(S)-2-methyl-1-phenyl-2-(pyridin-2-yl)propan-1-amine fumarate or apharmaceutically acceptable salt thereof and a pharmaceuticallyacceptable adjuvant, carrier, or diluent.